Method of adjusting axial direction of monitoring apparatus

Abstract

A method for a monitoring apparatus using a radar and a camera to detect an object. The radar and the camera each have its own detection area and the method is for detecting and correcting the displacement of each detection area by using a single target having dark and bright parts formed in a specified pattern on its surface and placing it in front of the apparatus where the two detection areas overlap. The direction and orientation of the detection area of the radar are measured and corrected and then the detection area of the camera is corrected. The pattern includes an elongated dark part flanked by a pair of bright parts such that quantity of reflected light obtained by scanning the detection surface has a distribution with waveform having two peaks and a valley in between and corrections on the detection areas are made by analyzing their positions.

Description

BACKGROUND OF THE INVENTION[0001]This invention relates to a monitoring apparatus such as a radar adapted to be mounted to a vehicle for using electromagnetic waves such as laser light to obtain position data of an object of detection such as a front-running vehicle and more particularly to a method of adjusting the orientation of its detection area, or its axial direction.[0002]Apparatus of this type adapted to be mounted to a vehicle for monitoring front-running vehicles or for cruising (or car-following) control have long been in development and it has been known to use electromagnetic waves including laser light for this purpose, or an apparatus adapted to transmit electromagnetic waves such as laser light to a target object of detection within a specified detection area and to obtain data such as the distance to the object from the delay time of a reflected signal therefrom.[0003]In the case of a laser radar, for example, a timing for light-emission is generated by a control ci...

AI Technical Summary

Benefits of technology

[0021]By such a method according to this invention, axial displacement of the monitoring apparatus in its rolling direction can be corrected easily because if there is an axial displacement to be correct, the aforementioned standard position on the target will come to be observed at a different position as the position of measurement is changed in the perpendicular direction. Since the observed position changes according to the magnitude of the displacement, the axial displacement can be easily corrected and the accuracy of the monitoring apparatus can be significantly improved.

[0039]In methods according to both the first and second embodiments of the invention, it is desirable to make use of a control device for the radar and / or the camera of the monitoring apparatus such that axial detection operations can be carried out automatically and also a processing device for automatically adjusting the position and orientation of the attachment of the monitoring apparatus or changing the parameter for the detection area such that the entire adjustment operations can be automated although some simple operations such as specifying a range and specifying crossing points may be done by a user. In such a case, the user has only to give a command after carrying out a simple operation such that complicated adjustments in the perpendicular direction need no longer be done by a person. Thus, the present invention contributes significantly to improving, for example, the efficiency in mass production of vehicles.

Problems solved by technology

For this reason, even after the axial direction is adjusted by a prior art method, a significantly large error could take place between the measured position by the monitoring apparatus and the actual position near the edge of a detection area because of such displacement in the rolling direction.

Moreover, since different targets are used individually for the axial adjustments of the radar and the camera by a prior art method, there was the following problem in the case of a fusion type which uses both a radar and a camera at the same time.

If the prior art method of axial adjustment is applied to the fusion type, there is the possibility that the relative positional relationship between the radar and the camera may become inappropriate (with the axes of the detection areas of the two sensors not being parallel or with the two sensors oriented differently with respect to the rolling direction) due to errors in the positions at which the targets or marks are set.

It is because there may be an error in the positioning of each target with respect to the vehicle that these errors accumulate between the sensors.

It is also because the displacement of each of the sensors from the direction of rolling is not adjusted that the orientations of their detection areas do not match in the direction of the rolling.

If the relative positional relationship between the two sensors remains thus incorrect, correlation between observed data by the two sensors used in the fusion method cannot be taken properly and this means that there is no advantage in using the fusion method.

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